fix(translate): resolve redeclared Responses tools to their latest declaration

packages/translate/src/composition/request/tool-names.ts

@@ -28,6 +28,13 @@ export const allocateToolNames = <Restored>(
   request: IRInputRequestHeader,
   inputTurns: readonly (IRInputTurnWithCallIds | RestoredAssistantTurn<Restored>)[],
 ): { readonly request: IRInputRequestHeader; readonly turns: readonly (IRInputTurnWithCallIds | RestoredAssistantTurn<Restored>)[]; readonly context: ToolNameContext } => {
+  const declared = new Set<string>();
+  for (const tool of request.tools ?? []) {
+    const key = callableKey(tool);
+    // One identity allocates one name, and these wires reject a repeated declaration name.
+    if (declared.has(key)) throw new TranslateInputException(`Cannot translate repeated declarations of tool '${tool.name}'.`);
+    declared.add(key);
+  }
   const callables = [
     ...(request.tools ?? []),
     ...inputTurns.flatMap(turn => turn.kind === 'restored' ? [] : turn.items.flatMap(item =>

packages/translate/src/ir/input/types.ts

@@ -54,7 +54,8 @@ export interface IRInputOutputFormat {
 // All
 export interface IRInputRequestHeader {
   readonly settings: IRInputSettings; // All
-  // Absent and empty are the same thing: a request that declares no tool.
+  // Absent and empty are the same thing: a request that declares no tool. Each
+  // callable identity appears once; a source that allows redeclaration resolves it.
   readonly tools?: readonly IRInputTool[]; // All
   readonly tool_choice?: IRInputToolChoice; // All
 }

packages/translate/src/protocols/openai-responses/as-source/input-to.ts

@@ -228,14 +228,10 @@ const selectorOf = (payload: CanonicalOpenAIResponsesPayload, selector: Record<s
   if (typeof selector.name !== 'string' || Object.keys(selector).some(key => key !== 'type' && key !== 'name')) {
     throw new TranslateInputException('Cannot translate namespace selector extensions.');
   }
-  const groups = [
-    ...(payload.tools ?? []),
-    ...payload.input.flatMap(item => item.type === 'additional_tools' || item.type === 'tool_search_output' ? item.tools : []),
-  ].flatMap(tool => tool.type === 'namespace' && tool.name === selector.name ? [tool] : []);
-  if (groups.length === 0) throw new TranslateInputException(`Cannot translate group selector '${String(selector.name)}' without a matching declaration.`);
-  return groups.flatMap(group => group.tools.flatMap(child => child.type === 'function' || child.type === 'custom'
-    ? [{ type: child.type, name: child.name, namespace: group.name } as IRInputToolSelector]
-    : []));
+  if (!toolInventories(payload).some(tool => tool.type === 'namespace' && tool.name === selector.name)) {
+    throw new TranslateInputException(`Cannot translate group selector '${String(selector.name)}' without a matching declaration.`);
+  }
+  return declarations.flatMap(({ type, namespace, name }) => namespace === selector.name ? [{ type, namespace, name }] : []);
 };
 
 const toolChoiceToIR = (
@@ -296,14 +292,22 @@ const toolGroupToIR = (tool: OpenAIResponsesTool): IRInputTool[] => {
 
 // A request can defer declarations to an inventory item inside the
 // conversation; those are tools like any other, not things the model said.
-const deferredInventories = (payload: CanonicalOpenAIResponsesPayload): OpenAIResponsesTool[] =>
-  payload.input.flatMap(item => item.type === 'additional_tools' || item.type === 'tool_search_output' ? item.tools : []);
+const toolInventories = (payload: CanonicalOpenAIResponsesPayload): OpenAIResponsesTool[] => [
+  ...(payload.tools ?? []),
+  ...payload.input.flatMap(item => item.type === 'additional_tools' || item.type === 'tool_search_output' ? item.tools : []),
+];
+
+// Codex declares a namespace in `tools`, again in `additional_tools`, and once
+// more after each compaction, so one callable can arrive many times. The latest
+// declaration is the caller's current statement of it; it takes the slot of the
+// first, which keeps the declared prefix stable for prompt caching.
+const latestDeclarations = (tools: readonly IRInputTool[]): IRInputTool[] =>
+  [...new Map(tools.map(tool => [JSON.stringify([tool.type, tool.namespace, tool.name]), tool])).values()];
 
 const openaiResponsesToolsToIR = (payload: CanonicalOpenAIResponsesPayload): Pick<IRInputRequestHeader, 'tools' | 'tool_choice'> => {
-  const declared = payload.tools?.flatMap(toolGroupToIR) ?? [];
-  const deferred = deferredInventories(payload).flatMap(toolGroupToIR);
-  const tools = declared.length === 0 && deferred.length === 0 ? undefined : [...declared, ...deferred];
-  const toolChoice = payload.tool_choice == null ? undefined : toolChoiceToIR(payload, payload.tool_choice, tools ?? []);
+  const declarations = latestDeclarations(toolInventories(payload).flatMap(toolGroupToIR));
+  const tools = declarations.length === 0 ? undefined : declarations;
+  const toolChoice = payload.tool_choice == null ? undefined : toolChoiceToIR(payload, payload.tool_choice, declarations);
   return {
     ...(tools === undefined ? {} : { tools }),
     ...(toolChoice === undefined ? {} : { tool_choice: toolChoice }),